The myth of the wish-granting magic lamp gets a masochistic twist in “The Brass Teapot,” a dark comedy about Alice (Juno Temple) and John (Michael Angarano), a young married couple as rich in love as they are strapped financially.

When Alice swipes the teapot from a thrift shop, thinking to get the couple on “Antiques Roadshow,” she finds it dispenses $100 bills whenever she or John gets hurt. Soon, they’re black and blue and rolling in cash, trying to innovate new forms of injury (Does the emotional kind count? What about witnessing other people’s pain?). Friends and relatives (Jack McBrayer, Alexis Bledel, Alia Shawkat and BobbyMoynihan) scratch their heads at the duo’s burgeoning fortune.

Temple and Angarano, entertaining enough, never quite sell the idea that this goodhearted couple would be so easily transformed by greed. Director Ramaa Mosley does demonstrate an eye for black humor in this feature debut, adapted from her comic book, but the cluttered third act distracts from the central query: Is ruthlessness toward yourself, your family, others the only path to serious wealth?